Various apparatus have been proposed for inputting a desired numerical value in computers or scrolling through a list of many display items that do not fit into a display panel to bring a desired hidden item into view.
For example, an input apparatus can be rolled with a finger of a user to scroll through the display items to bring a desired item into view from among hidden items or to perform other operations (see Japanese Patent Laid-Open No. 11-272378). This allows the user to flexibly control operations with the tactile sense of the finger or visual sense. Also, means for detecting the rotation speed and acceleration has been disclosed. Detected rotation speed and acceleration can be used to control the speed of scrolling without inputting an extremely large number of rotation angles.
Another apparatus has two buttons configured as personal identification number input means. An input numeric value is incremented according to how many times one of the buttons is pressed and how long the button is held down and the input value is confirmed by using the other button (see Japanese Patent Laid-Open No. 2000-207599).
These prior-art apparatuses displays data such as characters, words, sentences, address book data, phone numbers, indexes of audio and visual data, function items, and file names according to variation of speed and acceleration as well as rotation angle or the amount of rotation. However, the prior-art apparatuses have problems that such display does not allow visually impaired users to know which item is selected.
Furthermore, according to the prior art, an input numeric value can be incremented but cannot be decremented. This is inconvenient because if a user mistakenly enters a numeric value larger than intended, he or she cannot correct it or is required to start the input operation all over again.
The present invention has been made in view of these problems and an object of the present invention is to provide a data input apparatus and a data input method that allow a user to input numeric values in a simple and easy way.